[Marxism] (fwd from M Lause) PBS's Nova: " Dimming the Sun"
schaffer at optonline.net
Wed Apr 19 16:49:43 MDT 2006
[Mark: not sure why this bounced, i don't see anything obvious in the bounce log. Les]
Am I the only one who caught this documentary this week?
The documentary provides rather persuasive evidence that the amount of
sunlight actually reaching us on the earth's surface is declining,
though it varies from place to place. This is due to more particle
pollution in the air (around which larger amounts of water can condense)
and there's stuff up there like jet contrails (satellite pictures show
how these diffuse to cover a significant part of the sky in places-about
75% in the one they showed of southern California). This latter issue
became evident to the scientists when they observed the skies in the
days after Sept. 11 when air traffic was grounded. The impact of this
on the sunlight reaching us has been reflected in subtle changes like
the rate of water evaporation over the last 30 years. The figures given
for the overall diminishing of sunlight were unbelievably
high--something like 30% in parts of the old Soviet Union, 16% less in
the UK, etc.
According to the program, this bouncing sunlight back into space has
masked the actual impact of greenhouse gases in terms of heating things
up. So we face a much greater potential shift in average global
temperature than even the more pessimistic of us have expected.
They've also documented greater temperature fluctuations in terms of a
difference between day and night temperatures. This fits the idea that
you have a tension between two processes--a global heating up of the
planet from greenhouse gases and regionally variant factors reflecting
sunlight back into space.
I'd be interested in what others thought of the program and the
More information about the Marxism